Bacterial 3′UTRs: A Useful Resource in Post-transcriptional Regulation

Bacterial messenger RNAs (mRNAs) are composed of 5 ' and 3 ' untranslated regions (UTRs) that flank the coding sequences (CDSs). In eukaryotes, 3 ' UTRs play key roles in post-transcriptional regulatory mechanisms. Shortening or deregulation of these regions is associated with diseases such as cancer and metabolic disorders. Comparatively, little is known about the functions of 3 ' UTRs in bacteria. Over the past few years, 3 ' UTRs have emerged as important players in the regulation of relevant bacterial processes such as virulence, iron metabolism, and biofilm formation. This MiniReview is an update for the different 3 ' UTR-mediated mechanisms that regulate gene expression in bacteria. Some of these include 3 ' UTRs that interact with the 5 ' UTR of the same transcript to modulate translation, 3 ' UTRs that are targeted by specific ribonucleases, RNA-binding proteins and small RNAs (sRNAs), and 3 ' UTRs that act as reservoirs of trans-acting sRNAs, among others. In addition, recent findings regarding a differential evolution of bacterial 3 ' UTRs and its impact in the species-specific expression of orthologous genes are also discussed.